A magnetic sensor device disclosed in International Publication No. WO 2014-123142 (refer to Patent Literature 1) includes a magnet and a magnetic-resistance-effect-element mounted body. The magnet faces one surface of an object-to-be-detected having a magnetic component, has magnetic poles vertically-alternately arranged in the transport direction of the object-to-be-detected, and generates a cross magnetic field crossing the object-to-be-detected. The magnetic-resistance-effect-element mounted body is disposed between one of the magnetic poles of the magnet and the object-to-be-detected and outputs a variation in resistance value that indicates a variation in the transport direction component of the cross magnetic field caused by the magnetic component of the object-to-be-detected transported in the cross magnetic field. This magnetic-resistance-effect-element mounted body is disposed within the length of the one of the magnetic poles of the magnet in the transport direction at a position shifted in the transport direction from the center of the magnetic pole in the transport direction.
Another magnetic sensor device disclosed in Patent Literature 1 includes a magnetic circuit and a magnetic-resistance-effect-element mounted body. The magnetic circuit faces one surface of an object-to-be-detected having a magnetic component and generates a cross magnetic field crossing the object-to-be-detected at an interval between yokes, which are individually disposed at the center and the entry and exit sides spaced from the center in the transport direction of the object-to-be-detected. The magnetic-resistance-effect-element mounted body is disposed between a central yoke and the object-to-be-detected and outputs a variation in resistance value that indicates a variation in the transport direction component of the cross magnetic field caused by the magnetic component of the object-to-be-detected transported in the cross magnetic field. This magnetic-resistance-effect-element mounted body is disposed within the length of the central yoke in the transport direction at a position shifted in the transport direction from the center of the central yoke in the transport direction.
A magnetic sensor disclosed in Unexamined Japanese Utility Model Application Kokai Publication No. S62-68260 (refer to Patent Literature 2) includes a magnetic-resistance-effect-element mounted body fixed on a magnetic substrate, a permanent magnet fixed below the magnetic substrate, and a magnetic shield body disposed below the permanent magnet and having ends protruding upward.